Snap closure switch for one-way clutch drives



1964 R. s. ESHLEMAN 3,163,727

SNAP CLOSURE SWITCH FOR ONE-WAY CLUTCH DRIVES Filed Oct. 8, 1962 2 Sheets-Sheet 1 INVENTOR. RALPH G. ESHLEMAN A TTORNEY Dec. 29, 1964 R. G. ESHLEMAN SNAP CLOSURE SWITCH FOR ONE-WAY CLUTCH DRIVES 2 Sheets-Sheet 2 Filed Oct. 8, 1962 INVENTOR RALPH G. ESHLEMAN JZZMC 144M ATTORNEYY United States Patent ()fiice 3,163,727 Patented Dec. 29, 1964 3,163,727 SNAP CLtlSURE SWHTCH FUR QNEWVAY CLU'EEH DBiiVE Eaiph G. Eshlernan, Lancaster, Pin, assignor to Hamilton Watch Company, Lanes: er, Pa", a corporation of lennsylvania Filed @et. ti, 1962, Ser. No. 223,994 13 Claims. (till. mil-4:8)

This invention relates to electrical switching apparatus and, more particularly, to a snap closure switch for a one-way clutch useable in electrical timing motors.

Various timing motors have been provided in the past and are used in numerous applications where it is desired to drive an output shaft in a single rotary direction for a predetermined, accurate length of time. Some of the devices useable as electrical timing motors, incorporate watch or clock-type movements for timing purposes and include an electro-magnet for periodically rewinding the main spring of the timing movement. When the main sp 'ng runs down a pair of contacts are closed completing an electric circuit through the electro-magnet which, through the use of a suitable movable armature imparts a rewind kick or impulse to the main spring through a rotatably mounted i'lywheel. However, the gradual rundown of the main spring is usually accompanied by a correspondingly relative slow closure of the electrical contacts, thus subjecting the contacts at closure to substantial arcing. This undesirable arcing substantially reduces contact life and, therefore, the useable life of the timing motor.

The present invention provides an improved switching device for one-way clutch motors which insures a rapid and positive closure of the electrical contacts significantly decreasing the arcing at closure and improving the life of the unit. In the present invention, W1D the main spring runs down beyond a predetermined point the drive is disengaged through the clutch from the driven shaft and the contacts are spring urged into a rapid or snaptype engagement so as to insure rapid contact closure. This is accomplished through the use of a novel pivoted pawl .rrangement substantially reducing the complexity of the clutch mechanism and providing improved operation with increased reliability,

it is, therefore, one obiect of the present invention to provide a novel snap closure switch.

Another object of the present invention is to provide a rapid closure switch arrangement for one-way clutch drives.

Another object of the present invention is to provide a novel switching arrangement for timing motors.

These and further objects and advantages of the invention will be more apparent upon reference to the following specification, claims and drawings, wherein:

FIGURE 1 is an exploded View of the novel clutch and snap closure switch mechanism of the present invention.

FIGURE 2 is a partial cross section through a portion of the clutch mechanism of FEGURE 1.

FIGURE 3 is a plan view showing the relationship of the clutch and switch elements during the operation or drive portion of a timing cycle.

FIGURE 4 is a plan View similar to that of PlGURE 3 showing the relationship of the elements during the rewind portion of a timing cycle; and

FIGURE 5 is an exploded view showing the novel snap closure switch of the present invention incorporated in a timing motor.

While the novel snap closure switch of the present invention has general utility for use in conjunction with one-way clutch drives, it will be described in conjunction with an electrical timing motor having a watch type driving movement. Referring to FIGURES 1 and 2, the drive unit generally indicated at it comprises a rotor 12 freely pivoted on a rotatable shaft 14 having a bearing portion 16 of reduced diameter at its upper end about which freely rotates the hub 18 formed integral with the rotor 12. A wheel 29 is press fitted over the upper end of shaft bearing 16 and provides the upper endshake bearing for the rotor 12.

A pawl 22 is pivotally secured to one end of the rotor 12 by means of a stud fixedly secured in a suitable aperture 26 provided in the rotor. Pawl 22 is freely mounted to rotate about the shoulder 27 of the stud. The pawl lies in the same horizontal plane as wheel 2t Pawl 22 carries at its other end a pin 25; against which acts one end of a bias spring 3%. The other end of spring Ed is received in a suitable aperture 32 in the stud 24 and is suitably secured to the stud. The spring 39 is secured to the stud in such a manner as to bias the pawl 22 through contact pin 25; in an outward or radial direction about pivot shoulder 27. Mounted on a suitable support in the unit is an eccentric stop 34 which engages the outer end of pawl 22 as the pawl rotates with the rotor 12.

Rotor 12 is biased in the clockwise direction in FIG- URE 1 indicated as the run direction by a coiled main spring 36 having one end attached to suitable supporting structure in the unit and the other end attached to a post which, in turn, is rigidly secured to the end of rotor 12 remote from pawl A shown in FIGURE 1 shaft c nstitutes the output s aft and may drive a gear 37.

The end of rotor 12, to which the main spring 36 is attached is provided with a turned up flange 35 carrying a rotor contact dd. The contact is adapted to engage a similar contact on an armature dd. Armature 44 is pivoted about point 46 shown in HGURE 3 and is provided with a long curved arm and a shorter arm 56 on opposite sides of pivot 46. Energization of coil 52 of an electromagnet draws the shorter arm 5t towards the electromagnet about pivot 46 and causes the longer arm 48 of the armature to rotate in a counterclockwise direction in FIGURE 3 so that its contact 4-2 is brought into engagement with the rotor contact 4%.

FEGURE 3 shows the relationship of the elements during the run or drive portion of the cycle. During this period, the unwinding main spring 36 drives rotor 12 in a clockwise direction, as illustrated inwFlGURE 3. During this time, pawl 22 is :biased outwardly by spring 30 so that its inner edge 54 engages the outer periphery 56 of wheel 2% and power is transmitted to the shaft M from the rotor t?! through the wedging action of the pawl against the edge 56 of wheel 2d. As the main spring unwinds, the wheel 2d and shaft 1 rotate with the rotor 12 until the tail of pawl 22 comes into contact with the eccentric stop 34 suitably mounted on the unit plate work. Further rotation of the rotor 12 causes pawl 22 to pivot about stud 24 disengaging the pawl from the wheel 2% and freeing the wheel from the pawl. Rotor 12 is now disengaged from driven shaft 14 and is free to rotate about the shaft under the influence of main spring 36 until contact 46 of the rotor I12 engages armature contact 22 which engagement limits the clockwise movement of the rotor.

FIGURE 4 illustrates the position of the elements during the wind cycle which immediately follows. When rotor contact 4d engages armature contact 42 a suitable circuit is completed through the coil 52 of an electromagnet and the shorter arm 5% is drawn towards the coil causing the armature to pivot in a counter clockwise direction as indicated by the arrow in FEGURE 4 about pivot point 46. The electrical circuit can be traced from a suitable source of supply through coil 52, then armature 44, contacts d2 and 4t rotor 12, and main spring 36 to the grounded supporting structure of the unit. The armature 44 through contact 42 imparts a physical driving force to the rotor 12 in a counter clockwise or wind direction as also indicated !by the arrow in FIGURE 4. Rotor 12 is first driven by the physical force of moving armature 44 until the movement of the armature is ended by a suitable stop adjacent coil 52,. At this time rotor 12 continues to move in the counter clockwise direction under the influence of inertia and the electrical circuit between contacts 4-0 and 42 is broken as the inertial movement of rotor vi2 causes it to move away from armature 44.

Upon initial engagement with the stop 34 pawl 22 is rotated to free wheel 29 and during the rewind portion of the cycle the pawl 22 slides along the rim of Wheel 20. After the energy build-up in the rotor 12 has been dissipated in rewinding main spring 36 the rotor is again forced by the main spring in the clockwise direction illustrated in F-IGURE 3, the pawl wedges itself against the edge of wheel 29 and power is again transmitted to the shaft 14, thus completing a full cycle of operation. Adjustment of the eccentric stop 34.- provides adjustment of the gap between contacts 40 and 42 at the time of disengagement of the pawl 22 from the wheel 20.

FIGURE 5 shows the novel snap switch of the present invention incorporated in a watch type timing motor. In FIGURE 5 like parts bear like reference numerals. The entire unit is supported on a suitable base plate 6% and is provided with a conventional escapement 62 including a balance wheel 64, center arbor 66 and a third arbor 63. A mechanical output may be taken from the center arbor 66 through a suitable gear train and indicating hands, if desired. Likewise, an electrical output may be taken from the coil 52 of electromagnet 70 representative of the periodic impulses constituted by completion of the electric circuit through the coil of the magnet.

The center arbor 66 is journaled into a supporting plate 72 while the third arbor 68 may be journaled into a bracket 74 secured to plate 72. Wheel 20 and rotor 12 are mounted on the third arbor 63. Main spring 36 is connected to the rotor post 38 and to a similar post 76 on the stationary plate 72 by press iit washers such as 78.

The coil 52 of the electromagnet 70 is supported in a frame 80 which also carries armature 44 movable about pivot pins such as 46. Armature 44 may be spring biased in any conventional manner. Preferably a curved leaf spring (not shown) is connected to the armature and bears against spacer 82 so as to bias the shorter arm 56 of the armature away from the core of coil 52.

It is apparent from the above that the present invention provides a novel snap closure switch for a one-way clutch rewind mechanism which insures positive contact closure and avoids the excessive arcing occasioned by earlier constructions. When the rotor is declutched from the driven shaft by rotation of pawl 22 the rotor is free to move under the influence of the main spring so as to snap into rapid engagement with the armature so as to insure a rapid and positive contact closure with a minimum of arcing. The device is of a relatively simple, inexpensive construction and insures reliable operation over an extended lifetime. While only a single pawl arrangement is described, it is apparent that a plurality of pawls may be used, as desired, located in pairs spaced on diametrically opposite arms of the rotor. Similarly, while the edges of the pawl 22 and the edge 56 of the wheel 20 are indicated as smooth, they maybe provided with teeth, if desired.

The invention :may be embodied in other specific forms Without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the (ppended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

l. A snap closure switch for a unidirectional drive coinprising drive means and a driven member, clutch means including a movable contact coupling said drive means to said driven member, a. second contact positioned in the path of movement of said movable contact, and means for disengaging said clutch means just prior to the engagement of said contacts, said movable contact being mounted on a rotor, said drive means including a spring for driving said rotor.

2. A snap closure switch for a unidirectional drive comprising a rotor, a movable contact carried by said rotor, first means for driving said rotor in a first direction, second means including a second contact for driving said rotor in a second direction, a driven member, movable means coupling said rotor to said driven member whereby said driven member is driven by sm'd first drive means through said rotor and said movable means, and means for actuating said movable means to disengage said rotor from said driven member just prior to engagement of said contacts.

3. A snap closure switch for a unidirectional drive comprising a rotor, means for driving said rotor, a movable contact oarried by said rotor, a second contact positioned in the path of movement of said movable contact, a driven shaft including a wheel, means coupling said rotor to said wheel, and means for actuating said coupling means to disengage said rotor from said wheel at a predetermined spacing of said movable contact from said second contact.

4. A switch according to claim 3 wherein said drive means comprises a spring.

5. A switch according to claim 3 wherein said coupling means comprises a pawl pivotally mounted on said rotor.

6. A switch according to claim 5 wherein said pawl lies in the same plane as said wheel.

7. A switch according to claim 6 wherein said pawl frictionally engages the edge of said wheel.

8. A snap closure switch for a unidirectional drive comprising support means, a rotor mounted on said support means, a spring for driving said rotor, a movable contact carried by said rotor, a second contact positioned in the path of movement of said movable contact, a driven shaft including a wheel, a pawl pivotally carried adjacent the periphery of said rotor, said pawl coupling said rotor to said wheel, and stop means onsaid support means in the path of movement of said pawl whereby said pawl is pivoted by engagement with said stop means to disengage said rotor from said wheel at a predetermined spacing of said movable contact from said second contact.

9. A switch according to claim 8 including a bias spring for biasing said pawl into frictional contact with the edge of said wheel.

10. A switch according to claim 9 including an electromagnet having a movable armature for driving said rotor to wind said spring, said armature carrying said second contact.

11. A switch according to claim 10 wherein said electromagnet is energized by the closure of said contacts.

12. A snap closure switch for a unidirectional drive comprising a driving member and a driven member, said driving member alternately moving in first and second directions, said driving member including a movable contact, a second contact positioned in the path of movement of said movable contact, one Way clutch means coupling said driving member to said driven member, said driving member when moving in said first direction acting to drive said driven member through said clutch means and to simultaneously move said movable contact toward said second contact, said one way clutch means being disengaged when said driving member moves in said second 6 direction, and means for disengaging said one Way clutch means just prior to the closure of said contacts.

13. A switch according to claim 12 wherein said one Way clutch means comprises a movable pawl carried by said driving member and said disengaging means including an adjustable stop for moving said pawl away from said driven member just prior to engagement of said con- HICKS.

References Cited in the file of this patent FOREIGN PATENTS 645,527 Great Britain Nov. 1, 1950 

1. A SNAP CLOSURE SWITCH FOR A UNIDIRECTIONAL DRIVE COMPRISING DRIVE MEANS AND A DRIVEN MEMBER, CLUTCH MEANS INCLUDING A MOVABLE CONTACT COUPLING SAID DRIVE MEANS TO SAID DRIVEN MEMBER, A SECOND CONTACT POSITIONED IN THE PATH OF MOVEMENT OF SAID MOVABLE CONTACT, AND MEANS FOR DISENGAGING SAID CLUTCH MEANS JUST PRIOR TO THE ENGAGEMENT OF SAID CONTACTS, SAID MOVABLE CONTACT BEING MOUNTED ON A ROTOR, SAID DRIVE MEANS INCLUDING A SPRING FOR DRIVING SAID ROTOR. 